Here's the skinny: If you have a confirmed complimentary upgrade and want to remain in first don't stand by unless there are more seats open than waitlist. The app will tell you. Also understand that number can change quickly. Also understand the gate agent has to do some manual work and some won't. Hence why I rarely ever stand by. Otherwise, accept coach as the price for going earlier.

Irregular operations paid First (which DOES NOT include cash upgrades) is always at the top of the list even if not showing. A volunteer F standby gets more murky and again you're at the mercy of the gate agent.